1. Field of the Invention
This invention relates to the adhesive bonding of shapes for the aerospace and related industries.
2. Description of the Prior Art
There are factories and subcontractors who produce Adhesive Bond Assemblies, usually in autoclaves. They have established a history of success in preparing for and producing Adhesive Bond Assemblies in autoclaves.
Although they have established a successful history, bonding in an autoclave suffers from a number of disadvantages:
(a) The bond assembly details must be bagged and sealed with the tooling in order to pull a vacuum to apply pressure during bonding. This is expensive, recurring, material cost and requires hand labor.
(b) After placing the bond assembly in the autoclave, it can take a considerable amount of time for the autoclave to come up to temperature.
(c) It is very difficult to assure an even distribution of temperature within the autoclave and quite often large fans are used to stir the air in an effort to attain said distribution.
(d) Since efficiencies demand that several assemblies be bonded at the same time in an autoclave, it is sometimes necessary to wait until the conditions necessary to bond are met. An example would be if you want a bond cycle of 350.degree. F. at 35 psi and the next cycle is 250.degree. at 70 psi. Autoclave time must be scheduled.
U.S. Pat. No. 2,696,184 illustrates a thick rubber bladder that requires pouring to a pattern. My invention using sheet stock rubber, usually silicone, laid up on a metal cylinder or cone reduces the span time from approximately 2 weeks to 2 days to produce a bladder. The bladder of U.S. Pat. No. 2,696,184 is pump filled to form sheet metal blanks.
U.S. Pat. Nos. 2,416,137 and 3,025,208 reflect bag molding and an apparatus for adhesive bonding, but both are very expensive methods of manufacture.
My patent will limit the amount of gas or fluid to bond. The sheet stock rubber bladder can be produced rapidly and be mechanically lock sealed to a heater core. Heat and pressure can then be applied to bond. The details can be perforates such as those shown in U.S. Pat. Nos. 4,292,356 of Whitemore, 4,465,725 of Riel, 4,990,391 of Veta, and 5,041,323 of Rose as the pressure is contained within the bladder.